咔唑衍生物DiPICz载流子传输性能的理论研究

依据Marcus理论, 在密度泛函理论水平下对咔唑衍生物Dibenzo2,3: 5,6]pyrrolizino1,7-bc]indolo-1,2,3-lm]carbazole(DiPICz)的电子结构和传输性质进行系统研究. 计算结果表明, DiPICz的电子迁移率(5.81×10^-2 cm²·V^-1·s^-1)反常地高出空穴迁移率(6.02×10^-4 cm²·V^-1·s^-1)2个数量级, 表明稠合修饰可能是一种潜在的转变传输材料极性的手段. 分析发现, 导致DiPICz具有较好电子传输性质的原因在于相对较小的电子重组能和较好的晶体堆积方式. 在其鱼骨型堆积的晶体中, 存在着滑移的π-π及边对面的 CH…N和CH…π相互作用. 这些相互作用由于形成二维的电荷传输通道, 从而在电子传输中起着重要作用.

Theoretical Studies on Charge Transfer Properties of Carbazole Derivative DiPICz

Organic π-conjugated semiconductor materials have been extensively used in organic light-emitting diodes(OLEDs).Among them,carbazole derivatives are commonly used as hole-transporting materials.Here,the electronic structure and transport properties of dibenzo2,3∶ 5,6]pyrrolizino1,7-bc]-indolo-1,2,3-lm]carbazole(DiPICz) were investigated systematically by means of semiclassical Marcus charge transfer theory at the density functional theory level.The results indicate that the mobility of electron is 5.81 × 10-2 cm2·V-1·s-1,which is two orders of magnitude higher than that of hole(6.02×10-4 cm2·V-1·s-1),indicative of abnormal electron-transporting materials.We further proved that both the small electron internal reorganization energies and the character of higher-order molecular packing in its single crystals were crucial to good electron transport properties.In the ’herringbone’ packing of DiPICz crystal,the presence of typical slipped face-to-face packing and the formation of weak hydrogen bonds such as C—H…N and C—H…π interactions cause two dimensional electron transport networks,which play an important role in electron transport.